House Speaker John A. Boehner says it “really is inconceivable” that President Obama wouldn’t have known about the unfolding IRS scandal before learning about it from reporters, as the White House has claimed.

“It’s pretty inconceivable to me that the president wouldn’t know,” he said on Greta van Susteren’s Fox News program that aired late Wednesday. “I just put myself in his shoes: I deal with my senior staff every day, and if the White House had known about this, which now it appears they’ve known about it for about a year, it’s hard to imagine it wouldn’t have come up in some conversation.”

The Ohio Republican did concede that staff could have attempted to insulate Mr. Obama from the news, but with as many people involved in the investigation as there were, “it really is inconceivable that he wouldn’t have known.”

Lois Lerner, director of tax-exempt organizations for the IRS, tried to stop the Cincinnati field office’s targeting of tea party and other right-leaning groups by directing specialists in 2011 to broaden their criteria so that …